I'm looking for a GUI toolkit/framework to create applications that run on Mac Snow Leopard and preferably other systems(Windows, Linux).

Deal breakers:

X11 based

Non-native widgets

32 bit/Carbon

Bad Mac look and feel

As far as I know Tkinter runs X11 and wxWidgets and PyQT do not run 64 bit.

Is there anything usable for good looking Mac applications?

[edit]
http://wiki.python.org/moin/GuiProgramming
Lists a lot of unusable stuff, but has a few interesting ones.
Lucid... rings a bell, but the site has nothing about Python whatsoever.
PyGUI, looks like a cool one-man project, just like uxpython.

It seems QT, WX and TK are really the big ones...
All of them might have 64 bit or Cocoa ports in a few years, but a the moment none of them seems to run out of the box.

tkinter uses native widgets. X11 is merely an option (and not even the default option on the mac).
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Bryan OakleyJan 23 '10 at 15:25

They look native, but I can't believe they are. Native widgets don't allow switching to different styles. This is just like Swing.
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PepijnJan 24 '10 at 15:43

If they look native and they act native, who cares if they are really native or not. They are native though; just because you can switch themes doesn't make them not native. When you switch themes the widgets are simply recreated.
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Bryan OakleyJan 27 '10 at 12:29

The Apple-supplied Tk, Aqua Tk, on OS X has not been X11-based since at least OS X 10.4. Apple ships a 64-bit version of Aqua Tk in OS X 10.6 and the Tkinter in the Apple-supplied Python 2.6 is linked with it. There have been some reported problems using IDLE and other test applications with it, though. Your mileage may vary.

Can you confirm that TK uses native widgets? Or do they only look native?
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PepijnJan 24 '10 at 15:57

I'm not sure what you mean by "native widgets". You can see for yourself by running Python's IDLE or some of the Tk demos. Aqua Tk does not give you direct access to Interface Builder and the full-range of OS X user interface elements. If that is important to you, your best bet from Python is using PyObjC.
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Ned DeilyJan 24 '10 at 20:34